UNITED NATIONS - The United Nations' aid chief Valerie Amos signaled to the Security Council on Wednesday that it needed to take stronger action to gain greater aid access in Syria, but France said opposition by Russia to any robust moves created the "sad impression of a dead end."

Amos said the violence and humanitarian situation in Syria, ravaged by a civil war now in its fourth year, had only worsened since the council adopted a resolution two months ago that demanded safe and unhindered aid access, including across borders.

More than 150,000 people have been killed in Syria's three-year-old civil war. Some 2.5 million people have fled abroad and 9 million people inside the country need help, including nearly 3.5 million who have no access to essential goods and services.

"Far from getting better, the situation is getting worse," Amos said after briefing the 15-member council behind closed doors. "It's absolutely horrific what's happening day by day. Children, women, men are being directly targeted."

"The Security Council, in previous situations when we have seen this, have come together around humanitarian issues and have passed robust Security Council resolutions," she said.

Amos reminded council members on Wednesday that during previous humanitarian crises in Somalia and Bosnia "they had to pass a number of different resolutions under Chapter 7 to get us the humanitarian access that we needed."

A Chapter 7 resolution is legally binding and enforceable with military action or other coercive measures such as economic sanctions. Robust peacekeeping operations, including those in the Democratic Republic of Congo, South Sudan and Ivory Coast, are generally mandated by the Security Council under Chapter 7.

The resolution on aid access adopted by the council in February was binding, but not Chapter 7 and not enforceable.

The United Nations has said that cross-border aid deliveries could only be made without the consent of the Syrian government if authorized by a Chapter 7 resolution. It says aid access is currently only permitted through a handful of border crossings.

U.N. diplomats said Moscow would likely be opposed to a Chapter 7 resolution to allow cross-border aid deliveries.

LIKELY 'DEAD END'

Australian U.N. Ambassador Gary Quinlan said a "large number" of the council members would begin discussing what action could be taken to address the non-compliance with the February resolution drafted by Australia, Luxembourg and Jordan.

But French U.N. Ambassador Gerard Araud warned it was likely that little could be done by the council because Syrian ally Russia, a veto-wielding permanent member, would shield President Bashar al-Assad's government from any stronger measures.

"My personal feeling is, unfortunately, after what I have heard, nothing that we could table to the council could pass," he told reporters. "It's a sad impression of a dead end unfortunately."

Despite Russia's position, Araud said France was still planning to push forward with a resolution "in the coming weeks" to refer the situation in Syria to the International Criminal Court for possible war crimes indictments. Moscow has made clear it was against such a move.

Russia, supported by China, has protected Syria on the Security Council during the war. Russian U.N. Ambassador Vitaly Churkin said after Amos briefed on Wednesday that Moscow would not support imposing sanctions in a bid to increase aid access.

Dozens of top lawyers from around the world argued in a letter to the United Nations on Monday that there was no legal barrier for the world body to carry out cross-border aid deliveries or support other organizations to do the same.

"For every lawyer you will get three or four different opinions about international humanitarian law," Amos said.

"I don't feel that we should use precious time getting into an esoteric debate with respect to these issues of international humanitarian law. I think what we should be doing is focusing on how we best get the aid in," she said.